This neat little subwoofer and enclosure combo is reflex loaded and tuned to develop high level at low frequencies. Exploiting the natural boost in output found in most cars below 60 Hz known as “cabin gain”, the 8-inch single 4 Ohm; voice-coil subwoofer has a powerful motor that maximises efficiency. This makes the APBX 8 R the perfect companion to the Audison Prima AP8.9 bit amplifier. The low-resonant frequency of the subwoofer, matched to the reflex enclosure keeps excursion to a minimum within the entire audio spectrum offering exceptional output from a modest amplifier such as bridged channels of an Audison Prima AP4.9 bit / AP4 D delivering 260 W rms.